A mechanically adjustable planar tuning element, for millimeter and submillimeter wave planar integrated cir- cuits, has been developed and successfully demonstrated at 100 GHz. It functions analogously to a non-contacting waveguide backshort, with kn. I :-... Ã¢â‚¬â€0.3 dB, yet can be fabricated with the simplicity of a planar circuit and scaled for use throughout the millimeter and submillimeter wave spectrum.
Getting to wounded soldiers on the battlefield is a precarious task, and medics have a very high casualty
rate. It is therefore a vital importance to prioritize which soldiers to attend to first. The first step is to detect
life signs - if a soldier is dead or alive, and prioritize recovery of live soldiers. The second step is to obtain
vital signs from live soldiers, and use this to prioritize which are in most urgent need of attention. Our
team at Kai Sensors, University of Hawaii and University of Florida is developing Doppler radar heart
sensing technology that provides the means to detect life signs, respiration and/or heart beat, at a distance,
even for subjects lying motionless, e.g., unconscious subjects, wearing body armor, and hidden from direct
view. Since this technology can deliver heart rate information with high accuracy, it may also enable the
assessment of a subject's physiological and psychological state based on heart rate variability (HRV)
analysis. Thus, the degree of a subject's injury may also be determined. The software and hardware
developments and challenges for life signs detection and monitoring for battlefield triage will be discussed,
including heart signal detection from all four sides of the human body, detection in the presence of body
armor, and the feasibility of HRV parameter extraction.
Technology that can be used to unobtrusively detect and monitor the presence of human subjects from a distance and
through barriers can be a powerful tool for meeting new security challenges, including asymmetric battlefield threats
abroad and defense infrastructure needs back home. Our team is developing mobile remote sensing technology for
battle-space awareness and warfighter protection, based on microwave and millimeter-wave Doppler radar motion
sensing devices that detect human presence. This technology will help overcome a shortfall of current see-through-thewall
(STTW) systems, which is, the poor detection of stationary personnel. By detecting the minute Doppler shifts
induced by a subject's cardiopulmonary related chest motion, the technology will allow users to detect personnel that are
completely stationary more effectively. This personnel detection technique can also have an extremely low probability of
intercept since the signals used can be those from everyday communications. The software and hardware developments
and challenges for personnel detection and count at a distance will be discussed, including a 2.4 GHz quadrature radar
single-chip silicon CMOS implementation, a low-power double side-band Ka-band transmission radar, and phase
demodulation and heart rate extraction algorithms. In addition, the application of MIMO techniques for determining the
number of subjects will be discussed.
Technology for the detection of enemies from behind barriers and for securing of ports and perimeters with minimal
threat to warfighters is essential in modern threat scenarios. We are developing a network of small scattered Doppler
radar sensors which lie in wait and report on change or motion within a targeted perimeter. Most sensors are simple radar
receiver "nodes" capable of short range communications and long operation life with minimal power requirements,
while a few are more advanced radar transceiver "beacons" capable of active interrogation and long range
communications. Radar nodes and beacons could be scatter-deployed from a distance, creating a need for post-deployment
localization in order to provide useful reconnaissance. A beacon is designed to have absolute position
knowledge by strategic deployment of GPS, produces an interrogation signal, and analyzes locally received echoes for
signs of motion activity in the targeted area. Scattered nodes in the targeted vicinity form an ad-hoc network which also
receives and compares the beacon signal and its target echoes, and reports sensed activity to the beacon. This paper
introduces such a system and discusses radar node localization based on signal strength using kernel methods and
distributed learning algorithms which take energy constraints into account.
Because of their interesting electrical, mechanical and thermal properties at high frequencies, polymers are becoming more and more attractive in the development of RF and millimeterwave applications. Their process ease and characteristics indeed permit improvement in the performance of passive components as well as their integration especially with active devices. Investigated in this paper are a few technological solutions based on the use of thick polymer layers. The first one consists of a thick organic layer that may be employed as a dielectric membrane on bulk silicon micromachined substrates in order to realize suspended components, which exhibit thus very low losses and dispersion on a large frequency range. The elevation of passive circuits through thick polymers represents another attractive solution to minimize the losses induced by the silicon substrate, which through a low thermal budge provides a particularly attractive method for post-processing over active devices. The use of polymers for additional surface micromachining into coplanar slots on silicon substrates can also improve both losses and quality factor. Finally, an application using a thin polymer layer as dielectric protection for a MEMS device is described.
Modern communications demands have been steadily growing not only in size, but sophistication. Phone calls over copper wires have evolved into high definition video conferencing over optical fibers, and wireless internet browsing. The technology used to meet these demands is under constant pressure to provide increased capacity, speed, and efficiency, all with reduced size and cost. Various MEMS technologies have shown great promise for meeting these challenges by extending the performance of conventional circuitry and introducing radical new systems approaches. A variety of strategic MEMS structures including various cost-effective free-space optics and high-Q RF components are described, along with related practical implementation issues. These components are rapidly becoming essential for enabling the development of progressive new communications systems technologies including all-optical networks, and low cost multi-system wireless terminals and basestations.
Inductors are essential for fully integrated, complex RF circuits such as single chip radios. Both high Q, Q > 15, and high precision, +/- 2 percent, inductors are needed to meet phase noise specifications for on-chip VCO's and for reactive impedance matching to improve power transfer and linearity. We describe the design, test and simulation of self-assembled, micromachined inductors lifted away from the substrate by tensile stress in the metallization. The air gap reduces the capacitive coupling to the substrate, increasing both the Q and self-resonant frequency. For 2nH inductors we have measured Q-14 at 2GHz, with process variation < 2 percent. Increased temperature and current strongly increase the loss, but do not effect the inductance. The inductors are also relatively insensitive to mechanical excitation, with forces approximately 30g's required to significantly modulate the inductor loss under resonant excitation. Extensive EM simulations of this design methodology suggest that we should be able to reach Q > 25 at 2GHz and maintain 10GHz. We also compare these results with state of the art fully integrated Si RFIC planar inductors.